Diversity Of Ammonia-oxidizing Bacteria And Its Relationship With Water Environment In Lake-river Ecotone Of Poyang Lake

Ammonia oxidizing bacteria(AOB)have an important contribution in the natural nitrogen cycle.In the oxygen rich environment,ammonia oxidizing bacteria first convert ammonia into nitrite,and then nitrifying bacteria transform nitrite into nitrate.This process is called nitrification,and is an indispensable part of nitrogen biogeochemical cycle.Poyang Lake River and lake ecotone is the interlaced mixed area between the river ecosystem and the lake ecosystem in the Poyang Lake River Basin,which is affected by the advance and retreat of rivers and lakes,and the human activities on both sides of the Straits.Effect of ammonia oxidizing bacteria community and the nitrogen cycle function and the change of water environment on it,with the optimized management of water ecosystem health development and water quality in rivers and lakes,eutrophication prevention,and provide a scientific basis for the development and utilization of Poyang Lake,environmental planning,disease control and city water resources planning etc..Based on the construction of gene clone library of ammonia oxidizing bacteria,we explored the community abundance and diversity of ammonia oxidizing bacteria in Poyang Lake river lake ecotone,and studied how the ammonia oxidizing bacteria respond to the change of water environment.The results of the study are as follows:1.This study used 16 S rRNA gene sequence and amoA gene sequencing of two methods showed similar results,Poyang Lake Lake ecotone in AOB diversity along with the overall direction of open water to lakes showed increasing trend decline in the lake staggered,grassland diversity,and peak in the frequent human activities in the river the downstream area.2.The ammoxidation bacteria in the Poyang Lake River lacustrine ecotone are more abundant,and the corresponding dominant communities are formed under the same ecosystem in the same ecosystem.3.Poyang Lake Lake ecotone of ammonia oxidizing bacteria basically belong to Nitrosomonas and nitrosospira(Nitrosomonas)and Nitrosomonadaceae uncultured(Nitrosospira).The sequencing of amoA gene sequences can make up some shortcomings and shortcomings of the 16 S rRNA gene sequencing,and the ammonia oxidizing bacteria are more accurate.4.The pollution of Pb and Hg in Poyang Lake River and Lake Ecotone is more serious.The contents of nitrogen and phosphorus are over standard and partial eutrophication.The pollutants mainly come from the influence of human activities such as mining and smelting of non-ferrous metal deposits in the upper reaches of Poyang Lake basin.5.The composition,diversity and abundance of ammonia oxidizing bacteria community in Poyang Lake River and Lake Ecotone are mainly affected by water environmental factors,such as water temperature,pH,electrical conductivity,total nitrogen and total phosphorus content,and heavy metal ions.